Invasive ductal carcinoma, also known as infiltrating ductal carcinoma IDC是乳腺癌最常见的形式，占所有乳腺癌诊断的80%.

Pamela Wright, M.D., medical director of the Breast Center at Johns Hopkins’ Suburban Hospital, tells you what you should know about IDC, its diagnosis and advancements in treatment.

What is invasive ductal carcinoma?

乳管是乳腺(小叶)的乳汁流向乳头的通道.

Invasive ductal carcinoma 当生长在乳管内壁的异常细胞发生变化并侵入乳管壁以外的乳腺组织时，就会发生癌症吗.

Once that happens, the cancer cells can spread. They can break into the lymph nodes or bloodstream, where they can travel to other organs and areas in the body, resulting in metastatic breast cancer.

What are the symptoms of invasive ductal carcinoma?

“Like other breast cancers, IDC may present as a lump that you or your doctor can feel on a breast exam. But in many cases, at first, there may be no symptoms,” Wright says.

“这就是为什么筛查乳房x光检查对发现浸润性导管癌等乳腺癌很重要. A mammogram may detect a lump that is too small for you to feel, or suspicious calcifications in the breast, either of which will lead to further testing.”

According to Wright, 以下是浸润性导管癌和其他乳腺癌的可能征象. 如果你注意到这些，你应该马上联系你的医生做进一步的评估:

• Lump in the breast
• Thickening or redness of the skin of the breast
• Swelling or change in the shape of the breast
• Localized persistent breast pain
• Dimpling or retraction of the skin of the breast or the nipple
• Nipple discharge, other than breast milk
• 乳头上的鳞状或片状皮肤或乳房或乳头皮肤上的溃疡(疮). These can be signs of Paget’s disease, a different kind of breast cancer that can occur along with IDC.
• Lumps in the underarm area
• 乳头或乳房的外观变化与正常的每月变化不同

How is invasive ductal carcinoma diagnosed?

Several tests can help your doctor identify and diagnose IDC, including:

Physical exam. Manual examination of your breasts by your doctor can detect lumps and other changes. 如果你的医生感觉肿块或增厚，他或她可能会建议进一步的检查来排除IDC.

Digital mammography 一种改进的乳房成像方法是像常规乳房x光检查一样进行的吗. However, 在年轻患者和乳腺组织致密的患者中，它比传统的乳房x光检查更能发现癌症. 电子图像可以通过计算机辅助检测系统增强以发现质量, calcifications and abnormalities associated with cancer.

Breast ultrasound uses sound waves to examine the breast tissue and gauge blood flow. It is safe for examining pregnant patients, and does not use radiation.

Breast magnetic resonance imaging (MRI) uses a large magnet, radio waves and a computer that can detect small breast lesions, and may be especially useful in examining patients with a high risk of breast cancer, such as those with BRCA1, BRCA2 or other gene mutations associated with cancer.

Biopsy. A breast biopsy 包括从可疑区域提取乳腺组织样本，并将其送到实验室由病理学家进行显微镜检查, a doctor who specializes in identifying signs of disease. A biopsy can confirm or rule out the presence of cancer and, if cancer is present, reveal its characteristics.

Staging workup. When cancer is detected, the next step is staging. “Staging determines how far the cancer cells have spread,” Wright says. “分期是基于肿瘤的大小，以及它是否已经扩散到淋巴结或进入血液并扩散到身体其他部位.”

Invasive Ductal Carcinoma Treatment

“Treatment is based on the size and location of the cancer cells, the features or characteristics of those cells, and the staging,” Wright says. Depending on these factors, 你的医生会推荐一个包括以下一种或多种治疗方法的计划.

Surgery for Invasive Ductal Carcinoma

Breast cancer treatment has evolved to offer patients more options. In addition to removing breast cancer, 新的美容手术方法可以增强健康，减轻因癌症而失去全部或部分乳房的情绪影响. 综合乳房中心与协调团队的肿瘤和整形外科医生可以提供更广泛的选择.

Surgery for IDC may include one of these procedures:

• Lumpectomy is removal of part of the breast. It is also known as breast-conserving surgery. Lumpectomy may be followed by radiation treatments to treat any remaining cancer cells.
• Mastectomy is removal of the breast. Mastectomy is a treatment for patients with multiple, very aggressive, or large invasive ductal tumors. It can be followed by breast reconstruction.

Nonsurgical Invasive Ductal Carcinoma Treatment

Radiation. Radiation therapy might be part of your treatment plan if you are undergoing a lumpectomy. 研究表明，乳房肿瘤切除术后放射治疗IDC与乳房切除术一样有效. “我们通常不会在乳房切除术后对患者进行放射治疗，除非淋巴结中有一些癌症,” Wright says.

Chemotherapy. Deciding on whether to treat invasive ductal breast cancer with chemotherapy化疗取决于肿瘤细胞本身的特征——它们的基因和蛋白质. The more the doctor can learn about the characteristics of the cancer cells, 就越容易确定哪种类型的化疗(如果有的话)可能有效.

Hormone therapy. 激素受体阳性的乳腺癌可以用雌激素或黄体酮治疗. These medications come in pill form, and may be prescribed for several years.

Biologic (targeted) therapy. 这种方法使用抗体或小分子药物来激活你身体的免疫系统来对抗侵入性导管癌细胞.

Deciding on Invasive Ductal Carcinoma Treatment

Treatment for ductal breast cancer is not one size fits all. 你的医生会考虑几个因素来为你制定一个个性化的治疗计划, including how advanced the cancer is and the characteristics of the tumor or tumors.

赖特说，活组织检查可以揭示肿瘤对各种疗法的反应. For example, 分析可能揭示细胞表面存在某些蛋白质(如人类表皮生长因子2), or HER2) or hormone receptors for estrogen or progesterone. These characteristics can indicate tumors that can be treated with hormone therapy.

Checking for Ductal Breast Cancer in Lymph Nodes

“浸润性导管癌治疗的目标是将癌症从乳房中取出. 但如果癌细胞已经扩散到淋巴结，我们也可能需要切除淋巴结，”赖特解释说.

Your lymph nodes are part of your immune system. Lymph fluid from the breast drains into the axillary (under arm) lymph nodes. The number and location of axillary lymph nodes may be different from person to person.

A sentinel lymph node biopsy 是否有一项测试可以帮助你的医生决定切除淋巴结是否可以作为你癌症手术的一部分.

前哨淋巴结是浸润性导管癌首先出现的地方. 你的医生可以通过向乳房注射染料来识别前哨淋巴结，看看哪个淋巴结首先吸收了染料:这是前哨淋巴结. A sample of tissue from this node (biopsy) can reveal if cancer has spread there.

“If there’s no cancer in the sentinel node, the other nodes are OK and don’t need to be removed,” says Wright. “If there’s a small amount of cancer present, we’ll leave nodes in place and treat the area with radiation or use chemotherapy.

“如果我们在淋巴结中发现很多癌症，或者如果四个或更多的淋巴结受到影响, we perform an axillary lymph node dissection: surgery to remove the nodes.”

Rare types of invasive ductal carcinoma

Medullary ductal carcinoma accounts for only 3%–5% of breast cancers. It may appear on a mammogram, and it does not always feel like a lump; rather, it can feel like an abnormally spongy area in the breast tissue.

Mucinous ductal carcinoma is also called colloid breast cancer. It occurs when cancer cells within the milk duct of the breast produce mucous, which also contains breast cancer cells. The cells and mucous combine to form a tumor. Pure mucinous ductal carcinoma tends to grow slowly, and has a better prognosis than some other types of IDCs.

Papillary carcinoma forms finger-like projections (papules) that can be seen under a microscope. Many papillary tumors are benign, but even those that become cancerous are usually very treatable with a good prognosis. Papillary carcinoma most commonly occurs in people older than 60.

Tubular ductal carcinoma is a rare diagnosis of IDC, comprising only 2% of breast cancer diagnoses. 这个名字来源于癌细胞在显微镜下的样子——像数百个小管子. Tubular breast cancer has an excellent prognosis.

What is the prognosis for invasive ductal carcinoma?

你的医生会根据浸润性导管癌的特点和你的治疗效果来讨论你的预期结果.

专业中心，如约翰霍普金斯医学院的乳房健康服务中心，可以提供综合的乳腺癌专家团队，他们在手术方面有技能和经验, breast reconstruction, chemotherapy, biologic targeted therapy, radiation therapy and other hormonal therapies.

“Medical science is making great strides forward in treating breast cancer, 使我们的手术侵入性更小，改善手术效果和整体生活质量,” Wright says.